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Biomedical subjects

A K Poznanski

Publications and source records attributed to A K Poznanski.

At least 37 records · Page 2Linked to original sources
PubMed1994

Sequence and rate of bone marrow conversion in the femora of children as seen on MR imaging: are accepted standards accurate?

OBJECTIVE: The purpose of this study was to reassess the normal sequence and rate of marrow conversion in the femora of children as depicted on MR imaging. MATERIALS AND METHODS: We retrospectively analyzed 81 T1-weighted MR images of the femur for the appearance and distribution of hematopoietic (red) and fatty (yellow) marrow. Eighty-one children 2 days to 15 years old with no known bone marrow abnormalities were divided into four age groups. The signal intensity and homogeneity of the marrow in the proximal epiphysis, proximal metaphysis, diaphysis, distal metaphysis, distal epiphysis, and greater trochanter were compared with the signal intensity and homogeneity of surrounding muscle and fat and graded by two observers. In select cases, region-of-interest measurements of marrow, subcutaneous fat, and muscle were obtained to validate the visual grading system. RESULTS: Conversion of hematopoietic to fatty marrow in the femur followed a well-defined sequence, occurring first in the proximal and distal epiphyses, followed by the diaphysis, distal metaphysis, and then the proximal metaphysis. Although high-signal-intensity fatty marrow could be seen within the femoral diaphysis as early as 3 months of age, fatty marrow with various degrees of heterogeneity was routinely seen in this region by 12 months of age. After 5 years of age, the femoral diaphysis showed homogeneous high signal intensity. These findings are in contrast to previously published data that describe homogeneous red marrow within the femoral diaphysis during the first year of life and homogeneous yellow marrow visualized by 10 years of age. CONCLUSION: The normal age-related sequence of femoral marrow conversion we saw on MR images conforms to the sequence described in previously published reports, but this transformation, particularly in the diaphysis, occurs significantly earlier in life than has been previously reported. This discrepancy might be explained partially by the sensitivity of signal intensity in the femoral marrow to alterations in window and level settings.

Adolescent↗
PubMed1993

Effects of methotrexate on radiologic progression in juvenile rheumatoid arthritis.

OBJECTIVE: To assess the effects of methotrexate (MTX) therapy on radiologic progression in juvenile rheumatoid arthritis (JRA). METHODS: We evaluated serial wrist radiographs for carpal length in 23 JRA patients with bilateral wrist involvement, before and during MTX treatment. These carpal length measurements were compared with established norms for carpal length in a healthy pediatric population. RESULTS: Both clinical responders to MTX (17 of 23 patients) and nonresponders (6 of 23) had decreasing carpal length prior to initiation of the treatment. Eleven of the 17 clinical responders had improved carpal length after a mean of 2.5 years of MTX treatment. All 6 clinical nonresponders had progressive loss of carpal length. CONCLUSION: MTX treatment resulted in radiologic improvement, as measured by carpal length, in the majority of children with JRA who had a clinical response to MTX.

Arthritis, Juvenile↗
PubMed1993

Fatigue fractures of the sacrum in children: two case reports and a review of the literature.

We present the clinical and radiological features of two children with fatigue fractures of the sacrum. Both patients were active, had no underlying bone disease and presented with insidious onset of low back pain. Plain radiography was non-contributory to the diagnosis. In both patients a focal area of increased activity was present in the lateral aspect of the sacrum on bone scintigraphy, which corresponded to linear medullary sclerosis in the sacral ala demonstrated by computed tomography. Magnetic resonance imaging in one patient revealed a linear signal void in the sacral ala on T1- and T2-weighted images. This was surrounded by diffuse low marrow signal on T1-weighted images, and increased marrow signal on T2-weighted images. Fatigue fractures of the sacrum should be considered in the differential diagnosis of low back pain in children. An awareness of their appearance on magnetic resonance imaging is important as this modality is increasingly utilised, particularly in children.

Adolescent↗
PubMed1992

Radiological approaches to pediatric joint disease.

With the recent advances that have become available with imaging, we are able to gain considerable information about joint diseases. Although conventional radiography still plays a very important part in the diagnosis of joint disease, ultrasound, computed tomography, magnetic resonance imaging, and nuclear medicine studies have all enhanced our ability to evaluate joint disorders. Each of these modalities need not be used in every patient but when chosen carefully, can efficiently provide useful information both for diagnosis and management. These various modalities are also extremely useful to rule out the mimics of joint disease. Magnetic resonance has recently been shown to be useful in evaluation of dermatomyositis and of vasculitides in the brain.

Arthritis↗
PubMed1991

Autosomal recessive cerebellar hypoplasia and endosteal sclerosis: a newly recognized syndrome.

We describe a brother and sister and an unrelated boy with congenital cerebellar hypoplasia and endosteal sclerosis. All 3 children presented with ataxia and developmental delay, and were found to have microcephaly, short stature, oligodontia, strabismus, nystagmus, and congenital hip dislocation. A previously published case is reviewed. The disorder appears to represent a newly recognized autosomal recessive syndrome.

Cerebellum↗
PubMed1991

Evaluation of joint disease in the pediatric hand.

Juvenile rheumatoid arthritis, leukemia, hypertrophic osteoarthropathy, sickle cell disease, and child abuse can all be causes of joint disease in the child's hand. The role of radiology is to diagnose disease and follow disease progression so that therapy can be modified. Because much of the child's hand is unossified cartilage, measurements, bone mineralization, and maturation are important components of the radiologic evaluation.

Arthritis, Juvenile↗
PubMed1991

Useful measurements in the evaluation of hand radiographs.

Measurements are useful in the radiologic evaluation of the hand. They permit an objective evaluation of subtle alterations in the relative lengths of hand bones, which may be useful in the diagnosis of many congenital malformation syndromes. Evaluation of width of the carpus can be useful in the evaluation of juvenile rheumatoid arthritis as well as many bone dysplasias. Carpal angle measures, the relative position of the distal radius and ulna, as well as cortical measures of the second metacarpal have many clinical applications.

Anthropometry↗
PubMed1989

Ulnar variance in children--standard measurements for evaluation of ulnar shortening in juvenile rheumatoid arthritis, hereditary multiple exostosis and other bone or joint disorders in childhood.

Measurements for radioulnar variance in adults cannot be used in children because the epiphyses are not fully ossified. We describe a method of determining ulnar variance in children by using the distance from the distal metaphysis of the radius to the distal metaphysis of the ulna. Standards for this measurement are presented for ages 1.5 to 15.5 years in boys and girls. These measurements change little with age and may be helpful in establishing shortening of the ulna which may been seen in juvenile rheumatoid arthritis, hereditary multiple exostosis, or other bone and joint diseases with childhood onset.

Adolescent↗